http://www.susana.org/images/documents/07-cap-dev/c-training-uni-courses/available-training-courses/sandec-tool/03_water/index_03.htm
[Accessed: 18.02.2011]
Sandec Training Tool 1.0, Module 3 (2008) Presentation on the technical and non-technical aspects of sanitation household-level drinking water treatment and safe storage (HWTS) in developing countries.